[Xen-devel] [PATCH] Super Pages (2meg/4meg) patch

["Woller, Thomas" <thomas.woller@xxxxxxx>]

Attached is the latest super pages patch with the modifications
requested, the main content is consistent with Wei Huang's previous post
of this patch. 

applies to unstable 16877 cleanly.

There is a problem that I am working that is related to c/s 16728 (see
below), so the patch doesn't function quite yet with latest
unstable/staging (i.e. don't apply to staging quite yet).

Modifications from last patch:
xc_hvm_build.c/setup_guest
1) all the *_2MB variables are now *_super
2) the superpage size is now calculated (currently
   hardcoded to PAGE_SHIFT + 9 etc) from a single variable
   describing the order of a superpage (21 or 22)
3) the superpage size is determined by querying the xen capabilities:
   if Xen supports PAE HVM guests then superpages are 2MB, else 4MB.
   Currently using "if ( strstr(caps, "x86_32p") )" as a string match.

What is not done: 
1) I don't have crosscompile for IA64 and PowerPC compilation, I added
what I think are enough modifications to allow compilation without
runtime failure, but actual compiling will tell.

2) c/s 16728
Removing 16728 allows guests to start up. Get a "bad address" error
currently, but removing only the
xc_domain_memory_decrease_reservation(... [shared_page_nr-3]) call
(which frees up the guard page), then allows HVM guests to start up. I
am looking at the issue now, any ideas appreciated.

Testing:
1) ran over a week with PAE x86 hv without issue on 16656 base with HVM
guests. 
64b hv (sans 16728) does not show any issues starting up various HVM
guests with more limited testing.  Used both shadow paging and nested
paging during the testing.

2) in process of starting up 64b hv with patch for extended testing once
issue with 16728 resolved

3) don't plan on testing any 32b hv

Jan's recent 1Gig patch applies without failure on top of this latest
patch.

Please take a look at it, esp the newer mods to xc_hvm_build.c and the
powerpc/ia64 areas, and provide any comments.  it *should* be almost
ready to apply.

Cheers,

Signed-off-by: Tom Woller <thomas.woller@.com>

  --Tom

thomas.woller@xxxxxxx  +1-512-602-0059
AMD Corporation - Operating Systems Research Center
5204 E. Ben White Blvd. UBC1
Austin, Texas 78741

Attachment: super_pages_16877.patch
Description: super_pages_16877.patch

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